Mobile navigation systems in location-aware devices are now common. Mobile device navigation and car navigation systems have grown in popularity with the ability to provide up-to-date navigation information and visual map-based navigation aids to users en route.
Searching for particular points of interest (POIs) and alternate routes while en route can present problems in navigation systems because of the need to adjust the results based on the user's location. A common approach is to use a spatial search, such as for POIs within a certain radius of a current location. This approach cannot always return the best search results. Among other shortcomings, it fails to take into account the user's route, intended destination or the direction of travel.